Try doing a search, using the search function at the upper right corner. This issue has been discussed many times. There is info in the threads on how to repair at home. I opted to farm the job out to Palo Alto Speedometer http://www.paspeedo.com
, about a 3 day turn around, working great now.
'73 280SEL 4.5 (9/72)- RIP
Only 8,173 units built from 5/71 thru 11/72
'02 CLK320 Cabriolet - wifey's mid-life crisis
2012 VW Jetta Sportwagon TDI...at least its a diesel
Non illegitemae carborundum.